Microsoft has decided to block access to The Pirate Bay from Windows Live Messenger. When users try to send an instant message to a friend with a link from The Pirate Bay, Windows Live Messenger displays a warning, saying that the link is "blocked because it was reported as unsafe."

"We block instant messages if they contain malicious or spam URLs based on intelligence algorithms, third-party sources, and/or user complaints. Pirate Bay URLs were flagged by one or more of these and were consequently blocked," Redmond told The Register in an emailed statement.

The Pirate Bay has been a lightning rod of controversy for years now, as copyright holders take aim at the organisation for giving users access to their content. Much of the focus of last year's ill-fated Stop Online Piracy Act (SOPA) centered on stopping The Pirate Bay and other sites that provide a similar service. Still, The Pirate Bay sails on.

The Pirate Bay acknowledges that it faces a lot of enemies and is using a variety of tricks and tools to fight them off, including, we hear, airborne WiFi drones.

Although Live Messenger's apparent ban will block the standard Pirate Bay URL, users can easily share the link by adding a space or modifying it in other ways.